UI基础学习之（十五）：UIPickerView

#import <Foundation/Foundation.h>

@interface Province : NSObject

@property (copy, nonatomic)NSString *name;
@property (strong, nonatomic)NSArray *cities;

- (instancetype)initWithDic:(NSDictionary *)dic;

+ (instancetype)provinceWithDic:(NSDictionary *)dic;

@end

#import "Province.h"

@implementation Province

- (void)setValue:(id)value forUndefinedKey:(NSString *)key
{

}

- (instancetype)initWithDic:(NSDictionary *)dic
{
if (self = [super init]) {
[self setValuesForKeysWithDictionary:dic];
}
return self;
}

+ (instancetype)provinceWithDic:(NSDictionary *)dic
{
return [[self alloc] initWithDic:dic];
}

@end

#import "ViewController.h"
#import "Province.h"

@interface ViewController ()<UIPickerViewDataSource, UIPickerViewDelegate>

//数据源
@property (strong, nonatomic)NSArray *provinceData;

@property (strong, nonatomic)UIPickerView *pickView;

//显示选中的结果
@property (strong, nonatomic)UILabel *cityLabel;

@end

@implementation ViewController

//使用NSArray方式别人更改数据
- (NSArray *)provinceData
{
if (_provinceData == nil) {
NSMutableArray *provinceArr = [NSMutableArray array];
NSArray *array = [NSArray arrayWithContentsOfFile:[[NSBundle mainBundle] pathForResource:@"cities.plist" ofType:nil]];
for (NSDictionary *dic in array) {
Province *p = [Province provinceWithDic:dic];
[provinceArr addObject:p];
}
_provinceData = provinceArr;
}
return _provinceData;
}

- (void)viewDidLoad {
[super viewDidLoad];

/*
UIPickerView的属性和方法
@property(nullable,nonatomic,weak) id<UIPickerViewDataSource> dataSource;                // 数据源
@property(nullable,nonatomic,weak) id<UIPickerViewDelegate>   delegate;                  // 代理
@property(nonatomic) BOOL  showsSelectionIndicator;  // 是否显示指示器，默认是NO

@property(nonatomic,readonly) NSInteger numberOfComponents; //列的个数

- (NSInteger)numberOfRowsInComponent:(NSInteger)component; //列中的行数

- (CGSize)rowSizeForComponent:(NSInteger)component; //列中行的尺寸

// 返回一个自定义的view，如选择国旗，view可以是：国家名+国旗
- (nullable UIView *)viewForRow:(NSInteger)row forComponent:(NSInteger)component;

- (void)reloadAllComponents; // 刷新全部列

- (void)reloadComponent:(NSInteger)component; //刷新选中的列

- (void)selectRow:(NSInteger)row inComponent:(NSInteger)component animated:(BOOL)animated;  // 选中时的动画效果

- (NSInteger)selectedRowInComponent:(NSInteger)component; //获取选中列中的行号
*/

CGFloat screenW = [UIScreen mainScreen].bounds.size.width;

//设置label
self.cityLabel = [[UILabel alloc] initWithFrame:CGRectMake(0, 80, screenW, 30)];
self.cityLabel.backgroundColor = [UIColor clearColor];
self.cityLabel.textAlignment = NSTextAlignmentCenter;
[self.view addSubview:self.cityLabel];

self.pickView = [[UIPickerView alloc] initWithFrame:CGRectMake(0, 150, screenW, 200)];
self.pickView.delegate = self;
self.pickView.dataSource = self;
self.pickView.showsSelectionIndicator = YES;
[self.view addSubview:self.pickView];

//默认选中第0行0列  compmnent:列数  row:每列对应的行数
[self pickerView:self.pickView didSelectRow:0 inComponent:0];
}

//多少列
- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView
{
return 2;
}

//每列对应的行数
- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component
{
if (component == 0) {//多少个省份
return self.provinceData.count;
}else{
//当前选中的哪个省
//选中第一列中的行号
NSInteger pIndex = [pickerView selectedRowInComponent:0];
//取出对应的省会
Province *p = self.provinceData[pIndex];
return p.cities.count;
}
}

//代理
- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component
{
if (component == 0) {

Province *p = self.provinceData[row];

return p.name;

} else {

NSInteger pIndex = [pickerView selectedRowInComponent:0];
Province *p = self.provinceData[pIndex];

return p.cities[row];
}
}

//监听选中的方法
- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component
{
//选中第一列
if (component == 0) {
//刷新第二列的数据
[pickerView reloadComponent:1];
//选择第二列中的第一行（默认显示）
[pickerView selectRow:0 inComponent:1 animated:YES];
}

//获取选中的省 份名称
NSInteger pIndex = [pickerView selectedRowInComponent:0];
Province *p = self.provinceData[pIndex];

//获取选中的城市名称
NSInteger cIndex = [pickerView selectedRowInComponent:1];

self.cityLabel.text = [NSString stringWithFormat:@"%@ %@", p.name, p.cities[cIndex]];
}